1. Field of the Invention
Aspects of the present invention relate to a computer system, a control method thereof and a data processing apparatus, and more particularly, to a computer system that includes a plurality of memories corresponding to a plurality of channels, a control method thereof and a data processing apparatus.
2. Description of the Related Art
A computer system (such as a desktop computer, a laptop computer, and a mobile terminal) includes a memory (such as a RAM) to temporarily store processed data. The memory includes a main memory to read and write data processed by a main processor controlling the computer system (such as a central processing unit (CPU)), and a graphic memory to read and write graphic data processed by a graphic processor.
As users demand higher graphic quality, a graphic memory having a larger capacity is required. However, such a demand can also be accomplished by connecting a plurality of graphic memories. For example, two 64-bit graphic memories can be connected in parallel to thereby read and write data at a rate of 128 bits.
The graphic processor may include a graphic core that processes data to be read or written by a plurality of graphic memories. Specifically, the graphic core may process data of a plurality of channels, corresponding to the plurality of graphic memories, in a time division manner. Compared other types of data processing methods, in the time division manner, the graphic core consumes large amounts of power since the graphic core processes the data several times faster than the reading and writing speed of the graphic memory.
In a conventional computer system, however, the combined bandwidth of all channels (i.e., the bit rate of the processed data) is always fixed regardless of the amount of data to be processed. In reality, the amount of data to be processed, however, is not always the same. In some cases, a large amount of data may be processed (such as with 3D images), while in other cases, a small amount of data may be processed (such as with text). Furthermore, the amount of data to be processed may be rarely used (such as entering a screen saver mode, turning off a monitor, etc.).
If the large amount of data is to be processed, all of the channels normally operate to process the data as soon as possible. However, if all of the channels are used to process the small amount of data or the rare amount thereof, the processing would be inefficient and a waste of power. As described above, if the graphic core unnecessarily operates at a fast speed even though the amount of the data to be processed is small, the graphic core would be wasting power to the detriment of power saving measures. Particularly, studies have been implemented to reduce power consumption and extend battery usage time in a mobile computer system (such as a laptop computer). Considering such a recent trend, the unnecessary power consumption should be addressed.
Korean Patent First Publication No. 1999-0073440 discloses a mobile computer system that supplies only power to a memory that is necessary for operating software, and cuts off unnecessary power to the memory. However, the bandwidth of memory channels is not changed, and the unnecessary power consumption due to the graphic core is not addressed.
The graphic processor further includes a plurality of channel controllers that exchanges data of channels with respect to the plurality of graphic memories. In the conventional computer system, the plurality of channel controllers receives power and operates regardless of the amount of data to be processed. The plurality of channel controllers continuously receives power even when the plurality of channel controllers does not have a large amount of data to be processed. This continuous supply of power is another cause of unnecessary power consumption. Furthermore, the plurality of graphic memories unnecessarily wastes power in addition to the plurality of the channel controllers.